Test and Repair Procedures for 8T0895 Stud Tensioner Cylinder Group and 6V7047 and 5P5247 Hydraulic Puller Assemblies{1000} Caterpillar

Introduction

This publication contains testing, troubleshooting, repair procedures and parts information for 8T0895 Stud Tensioner Cylinder Group and 6V7047 and 5P5247 Hydraulic Puller Assemblies for 3600 Engines.

For information about parts listed without Caterpillar part numbers, please call the source companies as listed.

Do not perform any procedure, outlined in this publication or order any parts until you have read and understand the information contained within.

Reference: Engine Service Manuals.

8T0895 Stud Tensioner Cylinder Group

Necessary Parts and Tooling

Assembly Procedure for Cylinder Test Group

Illustration 1 Exploded View of Cylinder Test Group
(1) 5F4475 Bolt. (2) 0L1351 Bolt. (3) 4C5816 Collar Retainer. (4) 4C5817 Threaded Collars. (5) 8T0493 Cylinder Test Stud. (6) 8T0895 Stud Tensioner Cylinder Group. (7) 8T0494 Test Stud Spacer.

1. Assemble threaded collars (4), cylinder test stud (5), test stud spacer (7) and cylinder group (6). (See Illustration 1).

2. Install retainer (3) to cylinder group (6), using four bolts (1) and two bolts (2). (See Illustration 2).

Illustration 2 Assembled View of Cylinder Test Group
(1) 5F4475 Bolt. (2) 0L1351 Bolt. (3) 4C5816 Collar Retainer. (4) 4C5817 Threaded Collars. (5) 8T0493 Cylinder Test Stud (not shown). (6) 8T0895 Stud Tensioner Cylinder Group. (7) 8T0494 Test Stud Spacer. (8) 1P2375 Coupler Assembly.

3. Install two 1P2376 Coupler Assemblies to the 6D7726 Hose Assembly, part of the 8T3035 Lines Group. Install one end of the hose assembly to the hydraulic pump. Install the other end of the hose assembly to coupler assembly (8), located on the side of cylinder group (6). (See Illustration 2).

NOTE: 8T0820 Pressure Gauge must be attached to 3S6224 and 8S8033 Electric Hydraulic Pumps or 4C4865 Manual Hydraulic Pump.

4. Place the stud tensioner cylinder group with collar retainer (3) facing up. (See Illustration 2).

Test Procedure

NOTE: Before testing the stud tensioner cylinder group, insure the pump is not leaking and is operating properly.

High Pressure Test

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To avoid personal injury, do not stand above the collar retainer when testing the stud tensioner cylinder group. The stud tensioner cylinder group is tested with hydraulic oil under high pressure.

1. Start the hydraulic pump and apply pressure in 6890 kPa (1000 psi) increments, to a maximum pressure of 55 160 kPa (8000 psi). Turn the pump off and observe the pressure gauge. The pressure gauge should continue to read 55 160 kPa (8000 psi) for 5 minutes. This indicates the cylinder group can maintain HIGH pressure and does not leak.

2. Slowly release the pressure.

NOTE: A pressure loss may occur due to leakage in the lines group or couplers. Visually check the lines group and couplers to verify the leakage. Replace all parts that are leaking and retest the cylinder group.

Low Pressure Test

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To avoid personal injury, do not stand above the collar retainer when testing the stud tensioner cylinder group. The stud tensioner cylinder group is tested with hydraulic oil under high pressure.

1. Start the hydraulic pump and apply pressure slowly to 3450 kPa (500 psi). Turn the pump off and observe the pressure gauge. The pressure gauge should continue to read 3450 kPa (500 psi) for 5 minutes. This indicates the cylinder group can maintain LOW pressure and does not leak.

2. Slowly release the pressure.

NOTE: A pressure loss may occur due to leakage in the lines group or couplers. Visually check the lines group and couplers to verify the leakage. Replace all parts that are leaking and retest the cylinder group.

Troubleshooting Procedures

1. If the 8T0895 Cylinder Group can not maintain a constant pressure reading, then either the seals, rings and wiper, or relief valve may need to be replaced.

2. To determine which component is worn, refer to the topic entitled "Procedure to Determine if Internal Components Need to be Replaced", in this instruction.

To replace the seals, rings and wiper, or the relief valve, refer to the topic entitled "Repair Procedure", in this instruction.

3. If the stud tensioner cylinder group is able to maintain the pressures in the HIGH and LOW pressure tests, do not replace any parts.

NOTE: The presence of hydraulic fluid under the 8T0911 Cap does not necessarily indicate the seals are worn or there is a mechanical problem. The stud tensioner cylinder group is equipped with a 8T0901 Relief Valve. This relief valve is designed to open and relieve hydraulic pressure when the piston is extended too far. Hydraulic fluid from the relief valve will drain from the weep hole in the cap. Relieving the hydraulic pressure prevents the piston from extending out of the cylinder body, which would destroy the piston seals. Refer to the topic entitled "Procedure to Determine if Internal Components Need to be Replaced", in this instruction.

Procedure to Determine if Internal Components Need to be Replaced

NOTE: This procedure is used to determine if the O-ring seals, rings and wiper, or the 8T0901 relief valve need to be replaced

Illustration 3 8T0895 Stud Tensioner Cylinder Group Components
(8) 1P2375 Coupler Assembly. (9) 8T0908 Bolt. (10) 8T0906 Spring. (11) 8T0907 Spring. (12) 8T0913 Piston. (13) 8T0909 Wiper. (14) 8T0901 Relief Valve. (15) 5P6302 O-ring Seal. (16) 8T0915 Ring. (17) 8T0912 Cylinder Body. (18) 5J2383 O-ring Seal. (19) 9T0917 Ring. (20) 8T0911 Cap.

1. Remove coupler assembly (8) from cylinder body (17) and drain the hydraulic fluid from the stud tensioner cylinder group.

NOTE: Stud tensioner cylinder group must be fully retracted.

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To avoid personal injury, Do not stand above the 8T0911 Cap when removing 8T0908 Bolts. The cap is under a heavy spring load.

2. Remove bolts (9), in a pattern that will insure a slow release of spring force. Do not remove any of the bolts, until all bolts are loose.

3. Remove 8T0911 Cap (20).

4. Remove eight springs (10) and eight springs (11) from piston (12).

5. Remove all hydraulic fluid from surface of piston (12), with a clean towel.

Illustration 4
(1) 5F4475 Bolt. (2) 0L1351 Bolt. (3) 4C5816 Collar Retainer. (4) 4C5817 Threaded Collars. (5) 8T0493 Cylinder Test Stud (not shown). (7) 8T0494 Test Stud Spacer. (8) 1P2375 Coupler Assembly. (12) 8T0913 Piston. (17) 8T0912 Cylinder Body.

6. Assemble threaded collars (4), cylinder test stud (5), test stud spacer (7) to cylinder group. (See Illustration 4).

7. Install collar retainer (3) to cylinder body (17), using four bolts (1) and two bolts (2). (See Illustration 4).

NOTE: Tighten bolts (1) and (2) only until they bottom out in cylinder body (17). Over tightening of bolts (1) and (2) could cause damage to bolts.

8. Install two 1P2376 Coupler Assemblies to 6D7726 Hose Assembly, part of 8T3035 Lines Group. Install one end of the hose assembly to the hydraulic pump. Install the other end of the hose assembly to coupler assembly (8), located on the side of cylinder body (17). (See Illustration 4).

NOTE: 8T0820 Pressure Gauge must be attached to 3S6224 and 8S8033 Electric Hydraulic Pumps or 4C4865 Manual Hydraulic Pump.

9. Place the stud tensioner cylinder group with collar retainer (3) facing up. (See Illustration 4).

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To avoid personal injury, do not stand above the collar retainer when testing the stud tensioner cylinder group. The stud tensioner cylinder group is tested with hydraulic oil under high pressure.

10. Start the hydraulic pump and apply pressure slowly in 6890 kPa (1000 psi) increments, to a maximum pressure of 55 160 kPa (8000 psi). Inspect the cylinder group to determine if O-ring seals (15) and (18), rings (16) and (19), wiper (13) or relief valve (14) is leaking hydraulic fluid.

NOTE: The presence of hydraulic fluid under the 8T0911 Cap does not necessarily indicate the seals are worn or there is a mechanical problem. The stud tensioner cylinder group is equipped with a 8T0901 Relief Valve. This relief valve is designed to open and relieve hydraulic pressure when the piston is extended too far. Hydraulic fluid from the relief valve will drain from the weep hole in the cap. Relieving the hydraulic pressure prevents the piston from extending out of the cylinder body, which would destroy the piston seals.

11. Refer to the topic entitled "Repair Procedure", in this instruction, if repairs to the cylinder are needed.

Repair Procedure

NOTE: The parts and tooling required to perform the repair procedure are listed below.

Necessary Parts

Illustration 5 8T0895 Stud Tensioner Cylinder Group Components
(8) 1P2375 Coupler Assembly. (9) 8T0908 Bolt. (10) 8T0906 Spring. (11) 8T0907 Spring. (12) 8T0913 Piston. (13) 8T0909 Wiper. (14) 8T0901 Relief Valve. (15) 5P6302 O-ring Seal. (16) 8T0915 Ring. (17) 8T0912 Cylinder Body. (18) 5J2383 O-ring Seal. (19) 8T0917 Ring. (20) 8T0911 Cap. (21) 8T0903 Screen. (22) 8T0904 Ring. (23) 8T0899 Spring. (24) 1P7437 Cap. (25) 8T0902 Screw. (26) 2J5850 Pin.

1. Remove coupler assembly (8) from cylinder body (17), and drain the hydraulic fluid from the stud tensioner cylinder group.

NOTE: The stud tensioner cylinder group must be fully retracted.

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To avoid personal injury, Do not stand above the 8T0911 Cap when removing 8T0908 Bolts. The cap is under a heavy spring load.

2. Remove bolts (9), in a pattern that will insure a slow release of spring force. Do not remove any of the bolts, until all bolts are loose.

3. Remove cap (20).

4. Remove eight springs (10) and eight springs (11) from piston (12).

5. Remove piston (12) from body (17), by position the cylinder group on two wood blocks. (See Illustration 6). Remove piston (12) from body (17) by using a rubber mallet.

Illustration 6

6. Remove old relief valve (14) and install a new valve relief. Refer to the topic entitled "Procedure to Determine if Internal Components Need to be Replaced", in this instruction.

7. Install spring (23) and screw (25) using 9S3263 Thread Lock. Tighten screw (25) until spring (23) bottoms out. Then back out screw (25) 2 to 2 1/2 turns.

8. If replacement of 2J5850 Pin (26) is needed, remove pin (26). To install new pin (26) to the correct depth, press pin (26) until pin is bottomed out in body (17).

9. Remove O-ring seals (15) and (18) and rings (16) and (19) from piston (12), using a 5P1720 or 5P7414 Seal Pick.

Illustration 7 Proper Ring Installation

10. Install new O-ring seals (15) and (18) and rings (16) and (19) into piston (12). (See Illustration 5). Refer to the topic entitled "Procedure to Determine if Internal Components Need to be Replaced", in this instruction.

NOTE: Lubricate new O-ring seals (15) and (18) with hydraulic fluid before installation. When installing new rings (16) and (19), check the bevel ends of the rings for proper fit. Correct installation of the new O-ring seals and rings is critical to the operation of the stud tensioner cylinder group. (See Illustration 7).

11. Remove old wiper (13) and install new wiper. Refer to the topic entitled "Procedure to Determine if Internal Components Need to be Replaced", in this instruction.

NOTE: Lubricate wiper (13) with hydraulic fluid before installation.

12. Install piston (12) into cylinder body (17). Align pin (26) with hole in piston (12) and tap piston into body, using a rubber mallet.

NOTE: Lubricate piston (12) and cylinder body (17) with hydraulic fluid before installation.

13. Install eight springs (10) and eight springs (11) into piston (12).

14. Install cap (20) on cylinder body (17). Make sure the small vent hole in cap (20) is aligned with relief valve (14) in piston (12). Install bolts (9) and tighten to a torque of 34 N·m (300 lb in).

NOTE: Tighten bolts (9), in a pattern that will insure a slow increase of spring force. An improper tightening pattern can cause cap (20) to bind on piston (12). Damage to wiper (13) could result.

15. Install coupler assembly (8) into cylinder body (17). (See Illustration 5).

NOTE: Apply 5P3413 Pipe Sealant to threads coupler assembly before installation.

16. Refer to the topic entitled "Test Procedure", in this instruction, to verify the cylinder group is operating correctly.

6V7047 and 5P5247 Hydraulic Puller Groups

NOTE: For replacement parts in the following charts listed without Caterpillar part numbers, contact:

Illustration 8 Exploded View of 6V7047 and 5P5247 Hydraulic Puller Groups

Troubleshooting Hydraulic Puller Cylinder Groups

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The following troubleshooting and repair procedures should only be performed by qualified personnel familiar with this equipment.

1. Cylinder operates erratically.

2. Piston does not advance.

3. Piston extends only partly.

4. Piston advances slower than normal.

5. Piston advances but does not maintain pressure.

6. Cylinder leaks oil.

7. Piston will not retract or retracts slower than normal.

Problem 1: Cylinder operates erratically.

Probable Cause:

1. Air in system.

Bleed air and check for leaks.

2. Viscosity of oil too high.

Change to lower viscosity oil.

3. Internal leakage in cylinder

Replace worn packings.

Check for excessive contamination or wear.

4. Piston sticking or binding.

Check for dirt, gummy deposits or leaks as above.

Check for misalignment, worn parts or defective packing.

Problem 2: Piston does not advance.

Probable Cause:

1. Pump release valve open.

Close release valve.

2. Low or no oil in pump reservoir.

Fill with oil and bleed the system.

3. Air-locked pump.

Bleed the system.

4. Loose couplers.

Tighten couplers and bleed the system.

5. Plugged hydraulic line.

Flush and clean system.

6. Pump not operating

Check pump operating instructions

7. Load is above the capacity of the system.

Use the correct equipment.

Problem 3: Piston extends only partly.

Probable Cause:

1. Pump reservoir is low on oil.

Fill and bleed the system.

2. Piston rod binding.

Check for dirt, gummy deposits or leaks as above.

Check for misalignment, worn parts or defective packing.

Problem 4: Piston advances slower than normal.

Probable Cause:

1. Loose connection.

Tighten and bleed the system.

2. Leaky connection.

Clean and seal connection with a non-hardening pipe thread compound or teflon tape.

3. Restricted hydraulic line or fitting.

Clean or replace if damaged.

4. Pump not working correctly.

Check pump operating instructions

5. Leaky seals.

Replace seals.

Problem 5: Piston advances but does not maintain pressure.

Probable Cause:

1. Leaky connection.

Clean and seal connection with a non-hardening pipe thread

compound or teflon tape.

2. Cylinder seals leaking.

Replace seals.

3. Pump valve malfunctioning.

Check pump operating instructions.

Problem 6: Cylinder leaks oil.

Probable Cause:

1. Worn or damaged seals.

Replace seals.

2. Loose connections.

Tighten fittings.

Problem 7: Cylinder will not retract or retracts slower than normal.

Probable Cause:

1. Pump release valve closed.

Open pump release valve.

2. Couplers not fastened.

Fasten couplers.

3. Blocked hydraulic lines.

Clean and flush.

4. Weak or broken retraction springs.

Send to service center for repair.

5. Cylinder damaged internally.

Send to service center for repair.

6. Pump reservoir too full.

Drain oil to correct level.

Inspection, Maintenance, Cleaning and Storage of Cylinders

Cylinder Inspection

NOTE: Frequent and periodic inspection is necessary to insure proper operation of the cylinder groups. Below is a definition for both terms frequent and periodic inspection.

Frequent Inspection (usually once a month but in severe conditions, before each use) - Visual examination by the operator or other qualified personnel.

Periodic Inspection (yearly or sooner if the cylinder group condition suggests damage) - Visual examination by the operator or other qualified personnel.

Frequent and Periodic Inspection Procedures

1. Check for cracked or damaged cylinder housing.

2. Check for excessive wear, binding or other damage to the threads.

3. Check for leaking hydraulic fluid.

4. Check for scored or damaged piston rod.

5. Check for improperly functioning swivel heads and caps.

6. Check for loose bolts.

7. Check for damaged or improperly assembled accessory equipment.

8. Check for modified or altered equipment.

NOTE: A ram or cylinder head that is in of need repair must be clearly tagged and not used until all repairs are complete.

Cylinder Maintenance

1. All external moving parts on the rams and cylinders should be lubricated on a regular schedule.

2. Any exposed threads (male or female) must be cleaned and lubricated on a regular schedule.

3. If a ram or cylinder has been exposed to rain, snow, sand or grit laden air, it must be cleaned before it is used.

Cylinder Periodic Cleaning

1. A routine should be established to keep the pump as free from dirt as possible.

2. All unused couplers must be sealed with thread protectors.

3. All hose connections must be free of dirt and grime.

4. Any equipment hooked up to a cylinder should also be kept clean.

5. Use a clean premium grade hydraulic oil with a viscosity index of 215 SSU at 38°C (100°F) in this unit. Change hydraulic oil as recommended every 300 hours.

Cylinder Storage

1. Rams and cylinders should be stored in a vertical position and in a well protected area where they are not exposed to corrosive vapors, abrasive dust or any other harmful elements.

2. If a ram or cylinder has been stored for a year or longer it must be thoroughly inspected before it can be used.

NOTE: Many hydraulic service problems are caused by dirt or metallic particles in the hydraulic system. To avoid these problems, proper maintenance, including rust prevention and cleanliness, will help extend the life of your hydraulic system. Change the filter in the system if one is used.